Since storage devices such as hard disk drives are heating elements, they adopt a cooling configuration by using, for examples, fans when storage media are mounted in a plurality of chassis. For example, PTL 1 describes an apparatus equipped with a plurality of dummy units attached to an empty space of a chassis in such a manner that the dummy units can be freely attachable or detachable; and the dummy units are configured so that they can be extended or contracted in two steps (see PTL 1). Also, there is an apparatus configured to exhaust air from, and cool, the entire apparatus by means of the operation of exhaust air fans located in an upper part of a chassis and the operation of cooling fans on an HDD (Hard Disk Drive) module basis (see PTL 2). Furthermore, PTL 3 describes that: electric heating plates of high thermal conductivity are placed to extend from an area close to a heat source and across an upper end face area of a storage chassis; a radiator plate is placed via Peltier elements in the upper end area of the storage chassis for each electric heating plate; and an electric current which is caused to run through each Peltier element is controlled according to a temperature of each storage equipment (see PTL 3).
Incidentally, when expanded chassis loaded with, for example, storage devices are mounted in high density in a drive box or the like, a configuration is adopted such that an expanded chassis is pulled out from the front side of the drive box and a storage device(s) is inserted from a part of the drive box other than its front face.